2. EIGRP neighbor table — Tracks routers which have exchanged Hello packets. Hello packets are sent regularly out all interfaces participating in EIGRP to multicast address 224.0.0.10 in order to maintain neighborship. Neighbors are removed if no hello packet is received within the holdtime. Troubleshoot the neighbor table by using sh ip eigrp neigh or debug eigrp packets.

3. EIGRP topology table — After the router discovers its neighbors it is able to create the topology table and assigns successors and feasible successors. Passive is good, active is a bad state in the topology table, it is active because the router is actively attempting to find a path. DUAL acts upon the topology table to populate the routing table. Troubleshoot the topology table with sh ip eigrp top.

Other EIGRP Definitions:
— Advertised Distance — The metric from a neighbor to the destination network.

— Feasible Distance — The best metric to the destination network, including the metric to the neighbor advertising that path.

— Feasible Successor — Advertised distance is less than the feasible distance or current best path. This is called the feasibility requirement and this route will not result in a loop if installed in the routing table.

— Variance — EIGRP automatically load balance across equal-cost links. In order to turn on unequal cost load balancing use the variance command.